问题 填空题

(1)化学就在我们身边,化学与我们的生活息息相关。从氮气、二氧化碳、稀有气体、明矾四种物质中选出与下列用途相对应的物质,填写在空白处:

(1)①充入食品包装袋可以防腐的气体单质是        

②可做净水剂的是___ ___;

③充入灯管可以做霓虹灯的是__________;

④植物光合作用不可缺少的气体是___ __。

(2)用数字和化学符号填空:

①3个钠原子        

②2个氮分子        

③4个氢氧根离子        

④氧化镁中镁显+2价       

⑤碳酸钠         

答案

(1)①氮气;②明矾;③稀有气体;④二氧化碳

(2)①3Na;②2N2;③4OH;④;⑤Na2CO3

题目分析:(1)①氮气的化学性质不活泼,因此充入食品包装袋可以防腐,②明矾加入水中形成胶状物,使水中的不溶物沉降下来,③稀有气体通电时会发出不同颜色的光,因此充入灯管可以做霓虹灯,④二氧化碳是植物光合作用的原料。(2)根据化学符号及其周围数字的意义分析解答。①标在原子前面的数字表示原子的个数,故2个钠原子表示为2Na;②标在化学式前面的数字表示分子的个数,故2个氮分子表示为2N2;③根据离子的表示方法:在表示该离子的元素符号或原子团的右上角,标出该离子所带的正负电荷数,数字在前,正负符号在后,带1个电荷时,1要省略,由于1个氢氧根离子带2个单位正电荷,故可表示为OH+,4个氢氧根离子就在其前再加4,故表示为4OH;④根据化合价的表示方法:在其化学式中该元素的正上方用正负号和数字表示,且正负号在前,数字在后,则氧化镁中镁元素显+2价表示为MgO 。⑤根据化合物中元素的正负化合价的代数和为零,碳酸钠的化学式为Na2CO3

阅读理解

Psychologists in Britain have said that the last full week of January is the most depressing time of the year, and have labeled the Monday of that week “Blue Monday”, the most depressing day of the year. Mondays are generally seen as the worst day of the week because people feel grumpy(烦躁的) and tired at having to go back to work after a weekend with a different sleep pattern.

There are various reasons why more people feel depressed at this time of year. Many people have unpaid credit card bills for the Christmas presents they bought. As the party season is over, people feel stressed because they have to go back to real life — work and commuting; they may be unhappy with their body image after eating too many cakes, chocolates, and other food at Christmas-time. People may have already failed in their New Year’s plans, such as giving up smoking. The bad weather in January can also contribute to people feeling fed up.

Some companies are taking this quite seriously and offering suggestions for all the staff who are feeling depressed. They hope that helping people as soon as there are signs of depression will keep people from taking time off. Evidence shows that unreasonable managers who contribute to their staff feeling fed up at this time can expect an uncooperative (不合作的) workforce.

However, it’s not all bad! Many people feel optimistic at this time — that things can only get better. Psychologists offer suggestions of how to fight against feeling blue. These include spending 15 minutes doing a “gratitude exercise”, thinking about and writing down what you are grateful for, such as health, family, friends and so on. Taking up a new hobby, doing some exercise, going to bed earlier, eating a healthy breakfast, and listening to some cheerful music are all recommended (推荐) as ways to feel more cheerful.

68. How many reasons are mentioned in this passage for feeling depressed in January?

A. 2.            B. 3.           C. 4.           D. 5.

69. We can learn from the passage that if we say someone is blue, we mean he is ______.

A. wearing blue clothes          B. feeling down

C. very scared                    D. very worried

70. What can we learn from the passage?

A. Everyone feels depressed during the last full week of January.

B. Many workers leave their jobs during the most depressing time of the year. 

C. Some people are not sad in January as they know that all the following months will be better.

D. Psychologists are working hard on how to solve the “Blue Monday” problem. 

多项选择题